1. Field of the Invention
The present invention relates to a structure for mounting a locking collar having a turn-signal cancel cam onto the rotor of a cable reel which is secured to a steering device of an automobile. In particular, the present invention relates to providing an interfitted locking structure which assures the rotor and locking collar are efficiently assembled together in proper radial alignment without error.
2. Description of Background Information
In an automobile steering system, a cable reel is provided for housing electrical cable. In particular, the cable reel includes a casing attached to a rotor having an inner cylindrical hub. An external cylindrical area of the casing is fixed to a steering shaft. As a result, since the casing and rotor are assembled together, both parts rotate in unison as an assembly. In an annular hollow area between the casing and the rotor, a flat electrical cable is spirally housed, is wound or rewound in the hollow area in accordance with reciprocal rotation of the rotor which corresponds to steering wheel movement.
A conventional steering system including a cable reel rotor 1 and locking collar 4 are illustrated in FIGS. 6(A)-6(C). As part of an automatic canceling operation of a turn signal switch, locking collar 4 is provided with a cancel cam 7, and the locking collar 4 is mounted on rotor 1. A plurality of equally sized L-shaped securing grooves 3 are provided at equally spaced intervals of 90xc2x0 the outer perimeter of central axial hub 2. In a similar fashion, a plurality of equally sized securing protrusions 6 are provided at equally spaced intervals of 90xc2x0 on the inside perimeter of cylindrical sleeve 5 of the locking collar 4. The securing grooves 3 can be interlocked with any of the securing protrusions 6, and by doing so, rotor 1 and locking collar 4 may be connected together by inserting the securing protrusions 6 into the securing grooves 3, followed by rotation to engage final fitment. This configuration allows rotor 1 to be connected to locking collar 4 at various radial positions. However, because the securing grooves 3 and securing protrusions 6 are of equal size, the grooves and protrusions can be interlocked in any of the four positions. Thus, a problem may arise during the assembly process when cancel cam 7 is not aligned properly (i.e. clocked) with respect to a desired normal position.
If such an erroneous connection is made, not only is assembly time consumed to unlock the fitted connection, but also there is a higher probability of damaging the connection area of the locking collar and rotor. Therefore, extra care must be taken to avoid causing an erroneous connection. When such an error occurs, assembly time increases and productivity decreases.
The present invention was made in view of the aforementioned problem. An object of the present invention is to prevent an erroneous connection from occurring without lowering productivity when mounting the locking collar onto the cable reel rotor.
In order to solve the above problems, in a first aspect of the present invention a mounting structure is provided for fitting a locking collar to a cable reel rotor. The mounting structure includes, in a structure for mounting a locking collar equipped with a cancel cam to a cable reel rotor for mounting to a steering device of an automobile, a plurality of pairs of securing protrusions and inverted L-shaped securing recesses. The securing protrusions and recesses are arranged at predetermined distances in a peripheral direction on a peripheral surface of a cylindrically shaped central axial area of the rotor and on a cylindrical inner peripheral surface of the locking collar. The locking collar is configured to be mounted on the rotor following relative rotation after insertion of the collar from the lower side of the rotor, whereby, one pair among the plurality of pairs of securing protrusions and securing recesses are formed as a specific xe2x80x9cpositioningxe2x80x9d (or clocking) securing protrusion and a specific xe2x80x9cpositioningxe2x80x9d securing recess having sizes configured to be different from the sizes of other pairs, thereby causing connection at a normal position of the rotor and the locking collar and by preventing other securing protrusions from insertion into the xe2x80x9cpositioningxe2x80x9d securing recess.
For example, by configuring one pair to be smaller in size than the remaining plurality of securing recesses and securing protrusions, the smaller securing protrusions only are only allowed to be inserted into the corresponding smaller recesses. Therefore, it is impossible to connect the rotor to the locking collar at a position other than the desired normal position. The result is a system that positively prevents an erroneous connection from occurring. Also, the desired normal position for mounting the locking collar to the rotor can readily be identified, thereby making the mounting operation easier, which in turn, improves assembly line productivity.
In another embodiment, the xe2x80x9cpositioningxe2x80x9d securing protrusion and the xe2x80x9cpositioningxe2x80x9d securing recess may be made a larger size than the remaining plurality of securing protrusions and securing recesses. In this case, it is impossible for the xe2x80x9cpositioningxe2x80x9d (or clocking) protrusion to be interlocked with any of the securing recesses other than the xe2x80x9cpositioningxe2x80x9d secured recess having a larger size, which means that any connection at a position other than the desired normal position becomes impossible, thereby preventing an erroneous connection from occurring.
An additional benefit from the mounting system are closer connection tolerances between the locking collar and rotor, thereby, leading to an increased resistance to vibrational and shock forces in an axial direction that are likely to develop during vehicle operation.
In another aspect of the present invention, a mounting system for fitting a locking collar to a cable reel rotor is provided. The locking collar has an annular flange with an upper and lower side, an axially centered cylindrical rim connected to the upper side of the flange, and the cable reel rotor having an axial centered cylindrical hub with a distal end to which the locking collar is attached. The mounting system includes a plurality of securing recesses positioned on one of the outer perimeter of the distal end of the hub and on the inner perimeter of the cylindrical rim, one of the plurality of securing recesses having a different size than the remaining plurality of securing recesses. A plurality of securing protrusions are provided on the other of the inner perimeter of the cylindrical rim and the outer perimeter distal end of the hub, one of the plurality of securing protrusions having a different size than the remaining plurality of securing protrusions, wherein the plurality of securing recesses and protrusions are configured to interlock, thereby fixing the collar to rotor. Additionally, the different sized securing recess and securing protrusion are configured to interlock only with each other respectively, and when interlocked, simultaneously provide a failure proof radial alignment of the cancel cam to a desired normal position, and allowing the remainder of the plurality of securing recesses and protrusions to be interlocked together, thereby fixing the collar to rotor and positively eliminating an erroneous cancel cam alignment.
In other aspects of the present invention, the one of the plurality of securing recesses and one of the plurality of securing protrusions are smaller than the remaining plurality of securing recesses and securing protrusions. Alternatively, the one of the plurality of securing recesses and one of the plurality of securing protrusions are larger than the remaining plurality of securing recesses and securing protrusions.
In further aspects of the present invention, the plurality of securing recesses are provided on the outer perimeter of the distal end of the hub, and the plurality of securing protrusions are provided on the inner perimeter the cylindrical rim. Also, the plurality of recesses may each include an inverted L-shaped recess with a short leg of the L-shape oriented in an axial direction of the hub, and a long leg of the L-shape oriented in a radial direction of the hub, so that the securing protrusions are axially inserted into the short leg of L-shaped recess, after which the locking collar and the hub are relatively rotated to position the securing protrusions in the long leg of the L-shaped recess to prevent disengagement of the locking collar in an axial direction. Moreover, the long leg of at least one L-shaped recess may include a hooking projection to engage a respective one of the securing protrusions to prevent disengagement of the locking collar in a radial direction. Furthermore, an inner axially centered cylindrical sleeve may be provided on the upper side of the annular flange and positioned proximate an inner side of the cylindrical rim, so that the distal end of the hub is engaged between the cylindrical rim and the cylindrical sleeve.
According to other aspects of the present invention, the plurality of securing recesses may be provided on the inner perimeter of the cylindrical rim, and the plurality of securing protrusions are provided on the outer perimeter of the distal end of the hub. Also, the plurality of recesses may each include an inverted L-shaped recess with a short leg of the L-shape oriented in an axial direction of the hub, and a long leg of the L-shape oriented in a radial direction of the hub, so that the securing protrusions are axially inserted into the short leg of L-shaped recess, after which the locking collar and the hub are relatively rotated to position the securing protrusions in the long leg of the L-shaped recess to prevent disengagement of the locking collar in an axial direction. Furthermore, the long leg of at least one L-shaped recess may include a hooking projection to engage a respective one of the securing protrusions to prevent disengagement of the locking collar in a radial direction.
In another aspect of the present invention, an inner axially centered cylindrical sleeve may be provided on the upper side of the annular flange and positioned proximate an inner side of the cylindrical rim, so that the distal end of the hub is engaged between the cylindrical rim and the cylindrical sleeve.
In a further aspect of the present invention, an apparatus for a steering system of a vehicle is provided. The apparatus includes a rotor having an annular-shaped wall connected to a central axial hub, the hub having a distal connecting end opposite the wall, a locking collar having an annular flange with an upper and lower side and a cancel cam formed on the outer perimeter of the flange, wherein the flange is connected to an axially centered cylindrical rim. A mounting system for fitting the cylindrical rim to the distal connecting end of the hub is provided, and the mounting system includes a plurality of securing recesses positioned on the other of the outer perimeter of the distal connecting end of the hub and on the inner perimeter the cylindrical rim, one of the plurality of securing recesses having a different size than the remaining plurality of securing recesses. A plurality of securing protrusions are provided on one of the inner perimeter of the cylindrical rim and the outer perimeter of the hub, one of the plurality of securing protrusions having a different size than the remaining plurality of securing protrusions, wherein the plurality of securing recesses and protrusions are configured to interlock, thereby fixing the collar to rotor. Furthermore, the different sized securing recess and securing protrusion are configured to interlock only with each other respectively, and when interlocked, simultaneously provide a failure proof radial alignment of the cancel cam to a desired normal position, and allowing the remainder of the plurality of securing recesses and protrusions to be interlocked together, thereby fixing the collar to rotor, and positively eliminating an erroneous cancel cam alignment. Moreover, the apparatus for a steering system may further include any of the various aspects related to the above described mounting systems.